At the present stage of technology, burners operating at low pressure, that is to say at a pressure which is in general below 500 mbar, are subject to deterioration in the quality of combustion if the pressure of the supply falls below the nominal value for which they were designed.
In fact, the balance between the dosage of the injected gas fuel and the air combustive sucked in is only satisfactory within the limits of a restricted range below the nominal pressure.
This situation prevents the use of regulation by degressive variation of the pressure of the supply down to a minimum idling and leads to the use of an "all or nothing" regulation which thus requires an electrical reignition or a pilot-light.
It should be noted that this inconvenience resulting from the impossibility of obtaining a large range of regulation through variation of nominal pressure, without bringing about deterioration in the quality of combustion, diminishes and quickly disappears when the appliances are designed to operate at pressures higher than 1 Bar. In fact, the range of efficient carburation widens when the pressure increases, and therefore, with appliances designed, for example, to operate at a pressure of 1.4 Bar for the nominal rate, one can reduce the pressure down to an idling pressure of 0.02 Bar.
The problem thus concerns "low pressure" appliances, for example an appliance operating at a nominal pressure of 350 mbar for which the intake of air sucked in and the injection of gas provided by the injector do not remain proportional over a range of pressure falling below 50% of the nominal rate.
The present invention is intended to solve this problem and its essential aim is to supply a device for injection and regulation which allows the preservation of efficient carburation of the atmospheric gas burners designed to operate at low-pressure nominal rate when one wishes to modify their rate from the nominal pressure to minimum idling.